In the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) wireless communication networks, Hybrid Automatic Repeat Request (HARQ) Acknowledgement/Negative Acknowledgement (ACK/NACK) signaling corresponding to uplink (UL) transmissions is sent on the Downlink using a Physical Hybrid ARQ Indicator Channel (PHICH). The PHICHs are linked to the UL transmission Resource Block (RB) and grouped into PHICH groups of 8 PHICH for a normal cyclic Prefix (CP) and PHICH groups of 4 for an extended CP. The PHICH structure occupies an integer multiple of three REGs (REG=RE Groups with 4 data REs) with each group of 3 PHICH REGs supporting 8 PHICH or 1 PHICH group for normal CP and 2 PHICH groups for extended CP. The amount of PHICH resources reserved in a subframe by the network is configurable based on a 2-bit PHICH resource indicator Nh and the system bandwidth that is signaled on the P-BCH. The PHICH resource indicator indicates an integer number of PHICH groups.
3GPP R1-081071 describes the PHICH allocation scheme that is linked to the UL Physical Resource Block (PRB). It also puts a limit on the maximum value for the PHICH groups as ceil(N_PRB/4). 3GPP LTE however has not defined the dimensioning of the number of PHICH groups and the values for the 2-bit PHICH resource indicator Nh. Thus, there is a need for a mapping function for an appropriate PHICH group provisioning and for defining the signaling for PHICH resources for time division duplex (TDD) and frequency division duplex (FDD) including HD FDD. For TDD it is necessary to account for different TDD frame UL/DL multiplexing options when defining PHICH resource signaling.
The various aspects, features and advantages of the invention will become more fully apparent to those having ordinary skill in the art upon a careful consideration of the following Detailed Description thereof with the accompanying drawings described below. The drawings may have been simplified for clarity and are not necessarily drawn to scale.